Abstract: When operating in harsh environments, photovoltaic arrays are prone to various faults that can cause module performance degradation, reduced power generation efficiency, and potential safety risks. This paper reviews common fault types of photovoltaic arrays and analyzes the causes of short-circuit, open-circuit, grounding, and module cracking or micro-cracking faults. It further explores intelligent fault diagnosis methods for photovoltaic arrays based on visual image recognition, machine learning, and fuzzy reasoning. Finally, future development trends are discussed to provide references for improving the accuracy and efficiency of photovoltaic array fault diagnosis.